Noninvasive blood analyzers are known (e.g., WO97/24066) that are provided with a light source for irradiating parts of living tissue including blood vessels, an image capturing unit for imaging the irradiated blood vessels and tissue, and an analyzing unit for analyzing the obtained image. The analyzing unit includes an extracting unit for extracting an image density distribution showing a transverse distribution of blood vessels in the obtained image as an image density profile, a quantifying unit for morphologically quantifying the characteristics of the profile, a calculating unit for calculating the quantity of blood components based on the quantified characteristics, an output unit for outputting the calculation results, and living body inspecting apparatuses (e.g., WO99/00053). The living body inspecting apparatuses are provided with a base for positioning a part of a living body used as an examination object, side wall members which can hold the positioned part of the body from two sides, a light source supported by the base and the side wall members for supplying light to the living body, and a light-receiving unit for detecting optical information from the irradiated part of the living body.
Although the above-mentioned noninvasive living body measuring apparatuses are capable of simple transdermal blood analysis and continuous monitoring, it would be desirable to improve the analysis accuracy to a degree comparable to blood analysis by conventional blood sample collection.
In the living body inspection apparatuses described in PCT publications WO 97/24066 and WO 99/00053, since the measurement subject is a peripheral vein in a finger or the like, individual subdermal physiological differences in blood vessels and blood flow conditions in living bodies are the main causes of fluctuation in measurement values. These differences in physiological conditions are considered to be a factor regulating the limit of analysis accuracy.